openGL ES 学习第一课（绘制三角形和四边形）

openGL ES主要是用于嵌入式设备的3D图形的绘制

GLSurfaceView      GLSurfaceView.Renderer

效果如下：

直接代码：

1、GLRender.java

package wu.demo.www;import java.nio.IntBuffer;import javax.microedition.khronos.egl.EGLConfig;import javax.microedition.khronos.opengles.GL10;import android.opengl.GLSurfaceView.Renderer;public class GLRender implements Renderer {int one = 0x10000;//三角形的三个顶点private int[] triggerBuffer = {0, one, 0, //上顶点-one, -one, 0, //下左one, -one, 0, //下右};private int[] quaterBuffer = {-one, one, 0,one, one, 0, -one, -one, 0, one, -one, 0};private IntBuffer getVertexBuffer(int capacity, int sum[]) {IntBuffer vertexBuffer = BufferFactory.createIntBuffer(capacity).put(sum);vertexBuffer.position(0);return vertexBuffer;}public void onDrawFrame(GL10 gl) {//清除屏幕和深度缓存gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);gl.glLoadIdentity();//移动顶点,左移1.5，向里6个单位gl.glTranslatef(-1.5f, 0.0f, -6.0f);//移动好了后，设置顶点gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);//绘制三角形gl.glVertexPointer(3, GL10.GL_FIXED, 0, getVertexBuffer(9, triggerBuffer));gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);//重置观察矩阵gl.glLoadIdentity();//移动顶点,移动到右边gl.glTranslatef(1.5f, 0f, -6f);//绘制四边形gl.glVertexPointer(3, GL10.GL_FIXED, 0, getVertexBuffer(12, quaterBuffer));gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);//取消顶点设置gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);}public void onSurfaceChanged(GL10 gl, int width, int height) {float ratio = (float) width / height;gl.glViewport(0, 0, width, height);//设置投影矩阵gl.glMatrixMode(GL10.GL_PROJECTION);//重置投影矩阵gl.glLoadIdentity();gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);gl.glMatrixMode(GL10.GL_MODELVIEW);gl.glLoadIdentity();}public void onSurfaceCreated(GL10 gl, EGLConfig config) {//告诉 系统对透视进行修正gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);//白色背景gl.glClearColor(0, 0, 0, 0);//启用阴影平滑gl.glShadeModel(GL10.GL_SMOOTH);//设置深度缓存gl.glClearDepthf(1.0f);//启用深度测试gl.glEnable(GL10.GL_DEPTH_TEST);//所做深度测试 的类型gl.glDepthFunc(GL10.GL_LEQUAL);}}

2、BufferFactory.java

package wu.demo.www;import java.nio.ByteBuffer;import java.nio.ByteOrder;import java.nio.FloatBuffer;import java.nio.IntBuffer;import java.nio.ShortBuffer;/** * A utility class to create buffers. *  * All public methods are static. The Singleton pattern was avoided to avoid concerns about * threading and the Android life cycle. If needed, It can be implemented later given some research. */public class BufferFactory {// This class cannot and should not be instantiatedprivate BufferFactory() {}// We use Buffer.allocateDirect() to get memory outside of// the normal, garbage collected heap. I think this is done// because the buffer is subject to native I/O.// See http://download.oracle.com/javase/1.4.2/docs/api/java/nio/ByteBuffer.html#direct/** * Creates a buffer of floats using memory outside the normal, garbage collected heap *  * @param capacityThe number of primitives to create in the buffer. */public static FloatBuffer createFloatBuffer(int capacity) {// 4 is the number of bytes in a floatByteBuffer vbb = ByteBuffer.allocateDirect(capacity * 4);vbb.order(ByteOrder.nativeOrder());return vbb.asFloatBuffer();}/** * Creates a buffer of shorts using memory outside the normal, garbage collected heap *  * @param capacityThe number of primitives to create in the buffer. */public static ShortBuffer createShortBuffer(int capacity) {// 2 is the number of bytes in a shortByteBuffer vbb = ByteBuffer.allocateDirect(capacity * 2);vbb.order(ByteOrder.nativeOrder());return vbb.asShortBuffer();}public static IntBuffer createIntBuffer(int capacity) {ByteBuffer vbb = ByteBuffer.allocateDirect(capacity * 4);vbb.order(ByteOrder.nativeOrder());return vbb.asIntBuffer();}}

3、OpenGLTest1Activity.java

package wu.demo.www;import android.app.Activity;import android.opengl.GLSurfaceView;import android.opengl.GLSurfaceView.Renderer;import android.os.Bundle;public class OpenGLTest1Activity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);               Renderer render = new GLRender();        GLSurfaceView glView = new GLSurfaceView(this);        glView.setRenderer(render);        setContentView(glView);    }}